Fish Aid Antibiotics® Penicillin is an antibiotic that exerts a bactericidal action on gram-positive and some gram-negative bacteria in fish. Used in the control of some common bacterial diseases in fish, including diseases caused by bacteria such as fin and tail rot and Flexibacter infections.

Add one tablet (250 mg) into aquarium for each 10 gallons of water to be treated. Repeat in 24 hours. It is suggested that a partial water change be made between treatments. While duration of treatment depends on type and severity of the infection, it is recommended that extended baths in the medication continue for a minimum of 5 days but no more than 10 days. Discontinue treatment with this medication if no improvement is noted within 5 days.